Molecular cloning, expression, and in situ hybridization analysis of MnGPx-3 and MnGPx-4 from oriental river prawn, Macrobrachium nipponense, in response to hypoxia and reoxygenation.

Glutathione peroxidase (GPx) has been the focus of increased research because of its important role as an antioxidant and in reactive oxygen species (ROS) induced damage repair. Studies on GPxs have relevance with Macrobrachium nipponense because it has poor tolerance to hypoxia in Macrobrachium nipponense. The two subunits named as MnGPx-3 and MnGPx-4 according to the glutathione peroxidase nomenclature system. Both full-length cDNAs were cloned from the hepatopancreas. In this study, we analyzed the expression of two GPxs in Macrobrachium nipponense in response to changes in environmental oxygen. Expression levels of MnGPx-3 and MnGPx-4 indicated that both have strong responses to hypoxia. In situ hybridization showed that MnGPx-3 and MnGPx-4 were located in secretory and storage cells in hepatopancreas. These results suggest that GPx gene is expressed and released by secretory cells and released response to hypoxia. In the gill tissue, however, GPxs are located in blood cells, suggesting that they perform different functions in different tissues or organs. The results of in situ hybridization were consistent with those of quantitative Real-time PCR. This study provides a basis for understanding the oxidative stress response in M. nipponense under hypoxia.